Enduring visualization of complete needle in ultrasound beam won't be given during the whole procedure. For differentiation of complete needle visibility, partial or no visibility in in-plane UGRA, we will use needles with ultrasound visible marks (echogenic needles). If the objective observers will visualize all 3 marks and pole of the needle in ultrasound-image, needle is completely in-plane and visible for analysis. For partial visibility of marks we will use a needle visibility grading dependent to number of visible marks (One mark = poor visibility, two marks = middle visibility, three marks=good visibility). If there won't be visible marks in ultrasound image, needle is in absence and gets evaluated as "not visible".